1. Field Of The Invention
The present invention relates in general to illumination devices and in particular to an interlocking lens structure for a signal lamp.
Combination lens structures for signal lamps are frequently used in automobiles and boats. Such structures are usually formed of two or more mating molded plastic lens pieces. The plastic lens pieces cannot be formed simultaneously as an integral combination lens structure because the lens pieces are usually formed of different colors. Therefore, combination lens structures of this kind have been produced by one of several complicated methods.
2. Description Of The Prior Art
U.S. Pat. No. 2,841,697 to Smith discloses a lamp having adjustable lamp shade sections. Each of the lamp shade sections includes a frame sector and a panel sector, the panel sector being supported by and disposed around the frame sector. The panel sectors include slidably interfitting side edge portions. Each of the lamp shade sections further includes a supporting rod connected to and supporting the frame sector thereof. Guide means are formed on a lamp standard for slidably receiving complementary portions of the supporting rods for slidably supporting the lamp shade sectors relative to the lamp standard.
U.S. Pat. No. 3,803,402 to Nasu discloses a lens structure for a combination signal lamp. The lens structure comprises at least two lens pieces, each having a sidewall to be joined together. Each sidewall has upper and lower edges and vertical side edges. The sidewall of one of the lens pieces has at least one exposed, vertical dovetail groove having first and second ends, the first end being opened, and a horizontal notch joining the open first end. The sidewall of the other lens piece has at least one vertical dovetail projection having first and second end surfaces located at a site corresponding to that of the groove formed on the one lens piece. The projection is provided with a configuration complementary to that of the groove. The sidewall of the other lens piece further includes a horizontal flange extending from the first surface and having a configuration complementary to that of the notch.
U.S. Pat. No. 3,803,403 to Hasegawa discloses a lens structure for a combination signal lamp. The lens structure comprises at least two lens pieces, each having a sidewall to be connected together. Each sidewall has horizontal upper and lower edges and bilateral peripheral margins extending vertically between the edges. The sidewall of one of the lens pieces has at least one exposed, vertical dovetail groove. The sidewall of the one lens piece further includes grooves formed on its bilateral peripheral margins, the inner surfaces thereof lying in the same plane of the innermost surface of the dovetail groove. The sidewall of the other lens piece has at least one vertical dovetail projection adapted to fit in the dovetail groove and ridges extending from its bilateral peripheral margins adapted to fit in the peripheral grooves.
Other lens structures are illustrated and described in U.S. Pat. Nos. 2,954,461 to Tucker, D153,942 to Hussey, D216,151 to Cox, and D220,779 to Garcia.